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package com.oracle.truffle.regex.tregex.dfa;

import java.util.Arrays;

import com.oracle.truffle.regex.charset.CodePointSet;
import com.oracle.truffle.regex.tregex.automaton.StateSet;
import com.oracle.truffle.regex.tregex.automaton.StateTransitionCanonicalizer;
import com.oracle.truffle.regex.tregex.automaton.TransitionSet;
import com.oracle.truffle.regex.tregex.nfa.NFA;
import com.oracle.truffle.regex.tregex.nfa.NFAState;
import com.oracle.truffle.regex.tregex.nfa.NFAStateTransition;

public final class DFATransitionCanonicalizer extends StateTransitionCanonicalizer<NFA, NFAState, NFAStateTransition, DFAStateTransitionBuilder> {

    private final DFAGenerator dfaGen;

    public DFATransitionCanonicalizer(DFAGenerator dfaGen) {
        super(dfaGen.getNfa(), dfaGen.isForward(), dfaGen.isForward(), dfaGen.getOptions().isBooleanMatch());
        this.dfaGen = dfaGen;
    }

    @Override
    protected boolean canMerge(DFAStateTransitionBuilder a, DFAStateTransitionBuilder b) {
        TransitionSet<NFA, NFAState, NFAStateTransition> tsA = a.getTransitionSet();
        TransitionSet<NFA, NFAState, NFAStateTransition> tsB = b.getTransitionSet();

        long[] constraintsA = a.getConstraints();
        long[] constraintsB = b.getConstraints();
        long[] opA = a.getOperations();
        long[] opB = b.getOperations();
        if (!Arrays.equals(constraintsA, constraintsB) || !Arrays.equals(opA, opB)) {
            return false;
        }
        if (isPrioritySensitive()) {
            if (tsA.size() != tsB.size()) {
                return false;
            }
            for (int i = 0; i < tsA.size(); i++) {
                final NFAStateTransition tA = tsA.getTransition(i);
                final NFAStateTransition tB = tsB.getTransition(i);
                // implied by a.getTransitionSet().equals(b.getTransitionSet())
                if (!tA.getTarget().equals(tB.getTarget())) {
                    return false;
                }
                if (dfaGen.isGenericCG() && !(tA.getSource().equals(tB.getSource()) && tA.getGroupBoundaries().equals(tB.getGroupBoundaries()))) {
                    return false;
                }
            }
            return true;
        } else {
            return tsA.getTargetStateSet().equals(tsB.getTargetStateSet());
        }
    }

    @Override
    protected DFAStateTransitionBuilder createTransitionBuilder(NFAStateTransition[] transitions, StateSet<NFA, NFAState> targetStateSet, CodePointSet matcherBuilder, long[] constraints,
                    long[] operations) {
        if (dfaGen.isGenericCG()) {
            return new DFACaptureGroupTransitionBuilder(transitions, targetStateSet, matcherBuilder, constraints, operations, dfaGen);
        } else {
            return new DFAStateTransitionBuilder(transitions, targetStateSet, matcherBuilder, constraints, operations);
        }
    }

    @Override
    protected NFAStateTransition[] createTransitionArray(int size) {
        return new NFAStateTransition[size];
    }

    @Override
    protected DFAStateTransitionBuilder[] createResultArray(int size) {
        return new DFAStateTransitionBuilder[size];
    }
}
